Integrated cyclic process for producing metallic iron from iron oxidecontaining material



CROWLEY Feb. 8, 1955 2,701,762 INTEGRATED CYCLIC PROCESS FOR PRODUCINGMETALLIC IRON FROM IRON OxIDE-CONTAINING MATERIAL Filed Sept. 13. 1951 3Sheets-Sheet. 2

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H. L. CROWLEY Feb. 8, 1955 2,701,762 INTEGRATED CYCLIC PROCESS FORPRODUCING METALLIC IRON FROM IRON OXIDE-CONTAINING MATERIAL Filed Sept.15. 1951 5 Sheets-Sheet I5 I N V EN TOR, franz/zy HDD MMWR@ WTEGRATEDCYCLIC PROCESS FOR PRODUC- ING METALLIC IRON FROM IRON OXIDE- CONTAININGMATERIAL Henry L. Crowley, South Orange, N. J., assignor, by mesneassignments, to Henry L. Crowley & Company, Inc., West Orange, N. J., acorporation of New Jersey Application September 13, 1951, Serial No.246,466

8 Claims. (Cl. 75-34) 'Ihe present invention relates to an integratedcyclic process for producing metallic iron from iron oxidecontainingmaterial. More particularly, the present invention relates to a balancedprocess by which iron oxide-containing material may be processed,without going through the usual blast furnace and open hearth processesfor the recovery of iron therefrom, land by resorting to more strictlychemical methods, the process being adapted to raw materials which areleaner or poorer in iron content than those required for use in presentcommercial ferrous-metallurgy methods.

In the present process for the treatment of iron ores in the blastfurnace to make cast iron and subsequently in an open hearth to refinethis cast iron to eliminate many of the known impurities thereof, largeamounts of heat are required as well as other materials such aslimestone in order that the gangue portion of the ore be fluidized andseparable as such from the molten iron. As such, these known processesare practically restricted by economic limitations to handling orehaving a substantially high iron content, for example, an iron contentapproaching or exceeding 50%. Such iron ores are used up in the courseof time, at least in any given locality, so that that locality is forcedto use lower grade ores, which may still be available in abundantsupply, but are useful in accordance with conventional processes, onlyat a considerably higher cost per ton of iron produced. The lower gradeores may, however, provide the raw material for some new and essentiallydifferent process. The present invention provides such a new anddifferent process. This new process is practicable when applied torelatively low grade sources of iron, as it operates to lift the ironout of the accompanying non-volatile material or gangue, in a mannerwhich is substantially independent of the relative amounts of iron andgangue in the ore.

Certain of the detailed steps of the present process form the subjectmatter of separate applications, which will be referred to particularlyas the present description proceeds. The present process, however,covers the entire cyclic process, which is so integrated together as tothe several steps, re-cycling of some of the materials used, control ofthe ow of materials from one step to the next, etc. that the process asa whole is practicable, not only from a technical point of View, butalso from an economic point of view, to compete successfully with theknown process aforesaid in the production of metallic iron.

summarizing the present process, it comprises the steps of introducingan iron oxide-containing material, which may contain FezOa, FesO4 and/orFeO in any desired proportions as between each other and as comparedwith the total material present (including gangue) and may also containrelatively small amounts of metallic iron, into a chloridizing zone.This material is solid as introduced into the chloridizing zone andremains in the solid phase throughout this zone. 'Ihe chloridizing zonemay be constituted by one or more such part zones arranged at differentportions of a single piece of equipment, or arranged as a succession ofthe same or different types of pieces of equipment. In the chloridizingzone, whether this Zone is considered as a single zone or one or morepart zones, the solid material aforesaid is brought into contact with achloridizing gas, which contains as essential ingredients, HC1 andhydrogen. This gas may also contain more or less inert gas, such4 asnited States Patent O ICC nitrogen, and may also (in some' specialinstances) include some one or more reducing gases, such as carbonmonoxide. In any event, the gaseous mixture which is brought intocontact with the solid material in the chloridizing zone must includeHCl and hydrogen, irrespective of whether or not it includes some one ormore other gases.

The next step is to pass the solid material from the chloridizing zone,and at a rate which is preferably adjustably controlled into avaporizing zone. In this vaporizing zone the temperature is surlcientlyhigh so that ferrous chloride is vaporized and in this way is lifted outof the gangue and/or any remaining non-volatile materials. The gasesincluding vaporized ferrous chloride are thus separated from theremaining non-volatile materials in the vaporizing zone; and thenon-volatile materials, irrespective of their proportion in the originalraw material, may be discarded or used for any other desired purpose,forming no part of the present invention. It is noted that this solidmaterial is never melted during the process thus far described, so thatmuch heat is saved in this respect as compared with prior art processes.

The ferrous chloride vapor from the vaporizing zone is then conducted toa condenser or a condensing zone, wherein sufficient heat is abstractedfrom it, so that the material condenses to liquid form. It is, ofcourse, possible to condense the ferrous chloride completely to a solidform and thereafter melt it, but this mode of operation is usually notdesired by reason of the unnecessary loss of heat involved in thefurther condensation to solid form and the equivalent amount of heatwhich must again be introduced into the ferrous chloride to bring it toa molten state. It is desired in accordance with the present inventionthat the ferrous chloride be introduced into a reducing zone in theliquid state.

A second point or the sole control may be introduced into the cyclicprocess at this point thereof, in that liquid ferrous chloride may besuitably maintained in a storage tank therefor with suitable heatingmeans and/or heat insulation provisions to the end that the ferrouschloride will remain in the liquid state. The control of the flow ofliquid ferrous chloride from the storage reservoir to the reducing zonethus provides an additional or the sole control point for the operationof the process as a Whole.

The ferrous chloride is then introduced into a reducing zone in theliquid state and there brought into contact with a gas or gaseousmedium, the essential active ingredient of which is hydrogen. The liquidferrous chloride and the gas, including or consisting of hydrogen, mustbe introduced separately into the reducing zone as here-A inafter setforth. The reduction reaction occurs in this zone, resulting in thereduction of a large portion, but usually not all, of the ferrouschloride. The materials resulting from the reaction in the reducing zoneconsist, therefore, of reduced metallic iron in solid powder form, someunreacted hydrogen, HC1 produced by the reaction, some unreacted FeCl2,and any inert gases which were introduced with the hydrogen, includingin most instances some water vapor and possibly some nitrogen. Themetallic iron produced may then be separated from the remaining gaseousmaterials and unreduced ferrous chloride; and the materials other thanpowdered iron may be recycled in the process.

Two methods of separation of the products of the reducing reaction areincluded in the present invention. First, there is contemplated a hotseparation, that is, one in which all materials, other than powderediron, are converted into gaseous form, if they are not already in thisform, and are separated from the powdered iron by a separation asbetween gaseous and solid materials. For this purpose, it is necessaryto supply suflicient heat to the materials to be separated to vaporizeany liquid FeClz present, while at the same time preventing thecondensation of any other condensable gases or potentially gaseousmaterials. The solid iron remains in solid form. This solid iron is thenseparated by conventional means, for example, means similar to the wellknown cyclone type separators; and the gaseous materials are preferablyrecycled through to the chloridizing zone. this hot separation cycle,any ferrous chloride returned to the chloridizing zone with the recycledgases asaforesaid will be condensed in that zone due to the lowertemperatures maintained therein, and thereafter will be recycled in theprocess. Any excess hydrogen included in the gases being recycled fromthe reducing zone will also pass through the chloridizing zone and maythere be used to some extent in reducing any trivalent iron to bivalentiron. The HCl content in these recycled gases will be used in thechloridizing zone to convert the iron therein to ferrous chloride.

In the cold separation phase of the process, the products from thereducing zone will be cooled to the point where not only metallic iron,but also any remaining ferrous chloride will condense out in solid form.There will then be a separation effected between solid materialsresulting from this condensation and gaseous materials, particularlyincluding hydrogen and HCl, and possibly also including any inert gaseswhich may be present. It is preferable, even under these circumstances,that the temperature of the gases be kept sufficiently high, so that anywater vapor present therein will not con dense out. The gaseous materialresulting from this separation may then be returned to the chloridizingzone to react in that Zone in the same way as described in connectionwith the hot separation cycle. The solid materials resulting from thiscold condensation of the products from the reducing zone may then beseparated from each other, for example, by leaching out the ferrouschloride from the iron by use of a suitable solvent, followed byevaporation or other separation as between solid iron and the solutionof ferrous chloride. In the event that some organic solvent is used todissolve the ferrous chloride at this stage of the process, a suitablesolvent recovery system is contemplated for use, so that the solvent maybe recycled in the process and the ferrous chloride discharged for suchuse as may be desired therefor, or, alternatively returned to the cycle,for example, to the chloridizing zone or to the vaporizing zone.

The objects of the invention will be apparent from the foregoing. Whilethe principal features of the invention have been outlined above, thesefeatures will be brought out in greater detail in the followingdescription of some preferred embodiments of the invention, which areillustrated in the accompanying drawings, in which:

Figure 1 is a diagrammatic representation, with certain parts insection, of apparatus for carrying out the process of this inventionusing the hot separation phase of the process aforesaid;

Fig. 2 is a similar View of apparatus for the entire cycle adapted forthe cold separation phase of the process;

Fig. 3 is a foreshortened view, with parts principallyy in centralsection, illustrating a device which can be used to provide achlordizing zone or part zone;

Fig. 4 is a fragmentary view, principally in transverse vertical sectiontaken on the line 4 4 of Fig. 3;

Fig. 5 is a view, principally in central vertical section and somewhatdiagrammatic, illustrating an apparatus usable to provide a vaporizingzone for the process; and

Fig. 6 is a diagrammatic view of apparatus usable to provide a reducingzone for the process.

In considering the particular process contemplated in accordance withthe present invention, the` first point to consider is the compositionof the raw material supplied to the process. This material is hereindescribed generally as an iron oxide-containing material. The iron oxidecontent of this material may be in any one or more of the forms FezOa,Fe304 or FeO. There may also be present relatively small amounts ofmetallic iron. The remainder of the material may be of any desiredcomposition, so long as this composition does not substantiallyinterfere with any of the processes contemplated for use in accordancewith the present invention. Such other material may, therefore, beearthy or rock-type material, such as silica, which is completely inert.This other solid material may also include, for example, oxides of oneor more other metals, such as calcium or magnesium, which could reactwith the HCl in the chloridizing zone to form the correspondingchlorides, but wherein the chlorides would not be volatilizedv in thevaporizing zone along with the ferrous chloride, but would pass out inthe gangue and non-volatiles. It is further contemplated, that ifdesired, an original rawmaterial or ore could be pre-treated in someway, for` Iny 4 example, for reducing the iron content thereof to aferrous state with carbon monoxide, so that the iron oxidecontainingmaterial as supplied to the present process may include a part or allthe iron in ferrous form.

The raw material supplied to the process of the present invention shouldpreferably be sufliciently comminuted so that a desired intimategas-to-solid contact reaction can take place without having some of theiron oxide or iron physically protected from contact with the gases bysurrounding solid material. For this purpose, it is preferred tocomminute the raw material in any suitable way tol a particle size,probably about 48 to 50 mesh or smaller. Itis also preferred to have theraw ma-terial substantially dryv as it is supplied to the chloridizingzone in order to facilitate proper handling of the solid material' andto avoid the expenditure of any heat which otherwise might have to beused in evaporating water therefrom.

As shown in Figs. 1 and 2 of the accompanying drawings, this ironoxide-containing material is supplied in any suitable way, forming nopart of the present invention, to a suitable supply hopper 10. From thishopper the material is supplied at a desired and preferably controllablerate into a chloridizing zone here generally indicated as comprising afirst chloridizer 11. The supply of this raw material may be effected inany suitable way. As shown, thel material from the hopper 1t) maydischarge by gravity into a screw conveyor housing 12, in which isarranged a helical screw feed member 13, driven by a variable speedmotor 14 or other suitable source of power, the speed of which ispreferably controllable. From the housing 12, the raw material may thenpass through a passage means generally indicated at 15 under control ofa suitable means such as a star valve 16 to prevent the outow of gasesfrom the chloridizing zone through the solid material input passagemeans 15 and 12. If desired, means may be provided to purge the-incomingsolid material of included air or oxygen-containing gases, as by passingthrough some selected part of the solid material feeding system abovedescribed an inert purging gas, such as nitrogen. This will prevent theformation of a combustible gaseous mixture in the chloridizing zone dueto the presence of hydrogen in this zone as hereinafter particularly setforth. The means. by which thiszpurging of the solid material iseffected. arev not particularlyshown, as any suitable means may be usedfor this purpose.

In bothFigs. l and 2 of the accompanying drawings, theV chloridizingzoney consists of two chloridizers, the rst of which is shown at 11 andthe second of which is. shown at 17. The chloridizing Zone may generallybe comprised by one` or more independent pieces of apparatus withprovision for moving the solid material therethrough andv preferablywith independent control for the temperatures at different portionsthereof, although tlie last is not absolutely essential.

As shown in Figs. l and 2, the chloridizers 11 and 17` are substantiallyidentical. Again, this is not essential as the same or different typesof apparatus may be used in any desired sequence and mayy collectivelyconstitute a chloridizing zone. As shown in these two iig ures, thesolid material from the first chloridizer 11' is passed through asuitable passage 18 to a screw feed chamber 19 provided with a helicalfeed member 2) driven by a` suitable prime mover, such as a variablespeed motor 21.

In each of the chloridizers 11 and 17, there is illustrated asubstantially helical material feeding and agitating meansv 22, each ofwhich is driven by a suitable prime mover, again illustrated as avariable speed motor 23. Surrounding each of the chloridizers 17 and 22is a temperature controlling jacket 24 through which a temperaturecontrolling fluid may be passed for controlling the temperatures in thedifferent portions of the chloridizing zone. Each jacket 24 is providedwith inlet and outlet passages 25 and 26.

In starting up the apparatus, it is necessary to bring up thetemperature of the solid material in the chloridizingy zone byy theaddition'of heat to this zone. l'n some instances, however, after thechloridizing operation is progressing in a continuous manner, no furtherheat ad dition is necessary as the chloridizing reaction is excthermic,and in some cases, some heat may have to be withdrawn and dissipated.This may be done by suitablecontrol ofthe rfluid circulated through thejackets 24.

The temperatures to be maintained in the various portions of thechloridizing zone are generally from about 500 F. to about 1200 F. lnsome cases, it may be desired to operate with a progressively increasingtemperature gradient, following the teachings of the Graham et al.application, Ser. No. 127,428, led November 15, 1949, now Patent No.2,665,191, issued Jan. 5, 1954. In other instances, it may be desired tocarry on the chloridizing at a substantially constant temperature.

In general, the rate of the chloridizing reaction is increased withhigher temperatures, although the equilibrium to which this reactionproceeds may be more desirable under one set of temperature conditionsthan under another, as particularly discussed in the Graham et al.Patent No. 2,665,191 aforesaid. ln a preferred embodiment of theinvention which follows the cycle set forth in the Graham et al.application aforesaid, the temperatures for the solid material areprogressively raised during its passage through the chloridizing zonestarting, for example, with a temperature in the range from about 500 F.to about 800 F. in the first chloridizer ll, and rising to temperaturesin the range of about 800 E. to about 1200D F. in the second or lastchloridizer 117. This may advantageously be effected by passing heatedgases into the jackets 24 of each chloridizer adjacent to the exit endthereof and exhausting such gases from the jackets adjacent to the endsof the chloridizers through which the solid material enters. These gasesmay be controlled as to their temperature at or before they areintroduced into the jackets 24 and may, if desired, be furthercontrolled, for example, by diluting them with air from the atmosphereat one or more selected points along the jackets, in a manner not shown,but which will be obvious to those skilled in the art from thisdescription.

Each or either of the chloridizers 11 and 17 may, for example, besubstituted by a device constructed as particularly illustrated in Figs.3 and 4. ln these figures there is shown a substantially cylindricalhousing 27, which is provided at its ends with suitable bearing meansmeans (not shown), in which is journalled a central rorating shaft 28.The shaft 28 may also be journalled in a suitable bearing 29 mounted ona rigid structure adjacent to but outside the chloridizer. The shaft 28is provided with a plurality of spiders 30 supporting substantiallylongitudinal extending blades 31. lf desired, the blades 3l may be givena helical form, so as to assist in feeding the solid material from theentrance end portion of the chloridizer to the exit end portion thereof.downwardly to some extent from the inlet end toward the delivery end forthe solid material, so that the agitation of this material bylongitudinal blades Without a helical twist to the blades 31 may beeffective in conjunction with gravity to move the solid material fromthe inlet to the outlet end of the housing 27. Surrounding the housing27 is shown a substantially cylindrical jacket 32, which is provided ina manner not particularly illustrated with inlet and outlet means,through which a heated fluid, such as products of combustion, may becirculated for controlling and maintaining the temperatures of thematerials within the housing 27.

While there is illustrated and described in a general way two more orless similar types of equipment which may be used to provide achloridizing zone, it will be understood that other gas-to-solid contactequipment capable of withstanding the chemical effect of HC1 gas, theerosive eect of the solid material flowing therethrough, and thetemperatures involved as aforesaid, may be used in lieu of either orboth types of equipment herein illustrated and particularly described.

in the chloridizing zone, the solid material is brought into contactwith a gaseous mixture, the essential active ingredients or" which areHCl and hydrogen. The other gases which may be present in this mixtureinclude inert gases such as nitrogen, and under certain specialcircumstances some carbon monoxide, as has been discussed hereinabove inthe general summary of the invention. For the purposes of the presentapplication, only two gases are essential as constituents in thechloridizing zone, namely, HC1 and hydrogen.

In the chloridizing zone, iron in oxide form as FeO may be converted toferrous chloride; and further if the iron is introduced into thechloridizing zone in a trivalent condition as Fe2O3, it must also bereduced to a bivalent Alternatively, the housing 27 may be inclined 6condition. In the event that some or all the iron is introduced astrivalent iron oxide such as FezOa or FesOi, then the reduction of theiron to a bivalent condition preferably takes place substantiallysimultaneously with the chloridizing thereof, or immediately prior tosuch chloridizing as to any particular portion of the iron. This also isdiscussed to a substantial extent in the Graham et al. Patent No.2,665,191 aforesaid. lA relatively small amount of iron introduced intothe chloridizing zone in metallic form and any metallic iron formedtherein by reduction of any of the iron oxides by the reducing gaspresent (as hydrogen) may be converted to ferrous chloride by reactionwith the HCl present in the gases. In the event that reduction of theiron is required, hydrogen is present to effect such reduction. The HC1is present to effect a conversion of the iron to ferrous chloride. lnthe usual case, it is contemplated that the gases supplied to thechloridizing zone will pass therethrough in a direction substantiallycountercurrent to the flow of solid material through this zone. Hereagain, this is not essential, but is usually desirable and is theprocess illustrated in the drawings, Figs. 1 and 2.

The constituents of the entering gas, which have been describedaforesaid as to their essential ingredients, may now be described as toproportions. In these gases there should be about 2% to about 35% HClbased on the total of hydrogen and HCl. A preferred range of HC1concentration is restricted to the narrower limits of about 5% to about25% on the same basis. There may, in addition, be more or less diluentgases, the proportions of which to the combined hydrogen and HC1 totalis not particularly critical as long as there is suiiicient HC1 broughtinto contact with the solid material to chloridize the amount of ironwhich it is desired to chloridize. Usually, this will be all the ironcontent of the raw material, even though in some instances all this ironmay not be 100% chloridized in practice.

There are several ways in which the chloridizing step of the process maybe operated. If it is desired to use up all the HCl in the gases, sothat the gases leaving the chloridzing Zonewill contain substantially noHC1, then the rate of supply of the solid material supplied to thechloridizing zone may be maintained high in respect to the amount ofgases passing therethrough and particularly the HC1 content thereof.Under these circumstances, the HC1 efliciency of the entire process maybe kept at a maximum, even though at the cost of losing some iron, whichWillbe discharged with the gangue, usually as unchloridized iron oxide,but possibly including some metallic iron reduced from the oxide by thehydrogen present in the gases.

On the other hand, if it is desired to operate the process so as torecover the maximum amount of iron, while possibly losing some HCl, thenthe amount of raw material will be relatively less in respect to therate of supply of HC1 in the gases to the chloridizing zone. In thisway, little or none of the iron will be lost in the gangue, although thegases leaving the chloridizing zone may have some substantial HC1content. It is contemplated that some compromise between these twoextremes of operation may be preferred as by using a plurality ofchloridizers such as 11 and 17 as shown in Figs. 1 and 2 with asubstantially countercurrent flow of solid material and gases. In thisWay it is possible to use up almost all the HCI while converting almostall the iron to ferrous chloride.

It is further contemplated that more than two individual chloridizerscould be used if desired. Under such circumstances, for example, threeor more units could be provided with appropriate piping connections andmaterial handling connections, so arranged that some one, or any onechloridizer, could be by-passed for inspection or repair while using theremaining chloridizers. For example, if a third chloridizer were used,it could be operated in a temperature range of about 1000 F. to about1200 F. following the two chloridizers shown in the drawings, the thirdchloridizer being connected to the second chloridizer 17 in the same waythat that chloridizer is connected to the first chloridizer 11. Undersuch circumstances, HCl concentrations in the entering gases should berelatively high in order that the hydrogen present in this gas will notserve to reduce the ferrous chloride formed to metallic iron, which isundesired at this stage of the process. If under these circumstances,there is suflicient HCl present in the gases, any metallic iron,'whichmay have been formed in the earlier portions of the chioridizing zone,may be converted to ferrous chloride.

Thus, in general, the first chloridizer 11 or the iirst portion of thechloridizing zone from the point of view of solid material may be saidto be elfective to remove the last portions of the HC1 content of thegases by providing an ample amount of unchloridized iron oxide; thesecond or central section of the chloridizing zone is effective for suchreduction as may be necessary and chloridization in a relatively rapidmanner; While the last portion of the chloridizing zone or a thirdchloridizer, if such a third chloridizer be provided, is usable toobtain a relatively high yield of FeClz from the iron present bycontacting the solid material with a gas having a relatively highpercentage of HC1, and also for chloridizing any metallic iron formed byreduction of a compound of iron in any previous portion of thechloridizing zone to form FeClz.

The solid material from the chloridizing zone is then supplied throughto a suitable storage point indicated in Figs. l and 2 as a hopper 33.This is shown only diagrammatically in these figures; although inpractice the solid material will be moved by gravity or by the use ofsuitable conveyor means from the chloridizing zone into the hopper 33.Suitable means, such as a star valve 34,

may be provided for preventing gases from the chloridizing zone passinginto the hopper 33.

While the chloridized material is in the hopper 33, suitable means (notshown) may be provided for purging therefrom any hydrogen in the solidmaterial, so that when the ferrous chloride is vaporized from the solidmaterial in the vaporizing zone, there will be no hydrogen present toreact with the ferrous chloride vapor in this zone. This purging isnormally eifected by the use of an inert gas, such as nitrogen.

The next principal operation in the process is the vaporizing of theferrous chloride to lift it out of the non-volatile material, includingany gangue, which may have been present in the original raw material,and any non-chloridized oxides of iron.

As shown in Figs. 1 and 2, the material is supplied by gravity from thehopper 33 through a feeding means 35 to a vaporizer 36. The feedingmeans 35 may be provided as shown with a helical screw feeding device37, which may be driven by a variable speed source of power, such as avariable speed motor 38. The solid material may pass from the feedingdevice 35 by gravity into the left hand end, as seen in Figs. l and 2,of a tubular member 39, and be moved through this tubular member by anysuitable means such as a ram 40, driven by any suit- I able source ofpower (not shown) in a manner which will now be obvious to those skilledin the art. In the diagrammatic showing of the vaporizer 36 in Figs. land 2, there is illustrated a jacket 41 surrounding the tubular member39 and provided with inlet and outlet passages 42 and 43 for a heatingfluid such, for example, as hot products of combustion. Alternatively,any suitable and available source of heat may be provided for thevaporizing zone, which in this instance, comprises the tube 39.

In Fig. 5 there is shown a tubular member 44 located in a furnacegenerally indicated at 45. Heat may be supplied to` the furnace bycombustion therein. For this purpose there is illustrated a plurality offuel burners 46 supplied from a common supply line 47, products ofcornbustion leaving the furnace through a stack 48. The material may bemoved through the vaporizing zone by a ram 40, which is reciprocated ina conventional manner by any suitable means (not shown). Solid materialsmay be supplied to the tube 44 through a passage 49. Ferrous chloridevapor may leave the tube 44 through a means indicated at 50 and passthence to a condenser or condensing zone hereinafter described. Solidmaterial from which the volatile portions have been vaporized may passthrough to the right hand end of the tube 44, as seen in Fig. 5, andmove by gravity through a passage 51, which may be provided with meansfor permitting the removal of this solid material without introducingany diluent gas or permitting the escape of gas from the vaporizer. Suchmeans in the present instance comprises a portion of the passage meansS1 provided with spaced apart valves 52 and 53. The solid material maythen be taken to any suitable disposal point and used for any desiredpurpose for which it is adaptable.

While it is contemplated that ferrous chloride could be distilled out ofsolid material by a simple distillation op erationy and thereby belifted away from this solid material, it may be desired to pass acarrier or sweep gas through the vaporizing zone. Such a gas willnormally be an inert gas, as nitrogen, and will be supplied through thevaporizing zone in a manner more particularly hereinafter described. Dueto the partial pressure of this carrier gas, the vaporization pointtemperature of the ferrous chloride will be somewhat less than it wouldotherwise be. Thus, there is attained a minimum heat supply requirementfor the vaporizing zone by reason of the lower temperature required tobe maintained in this zone. This will result in corresponding savings invarious parts of the process as will be obvious to those skilled in theart.

The ferrous chloride vapor passing from the vaporizing zone ispreferably puried in any suitable manner to remove therefrom anyentrained solid particles. The means for accomplishing this purpose arenot shown in the drawings as such means are substantially conventionalwhenever relatively pure gases are required. This means may, therefore,take the form of one or more conventional ltering means.

As it is the purpose of the present application to effect the reductionof the ferrous chloride in the liquid phase, the next operation whichmust take place is the condensation of the ferrous chloride vapor toferrous chloride liquid. ln this Way, the present applicationdistinguishes from my copending application, Ser. No. 224,770 filed May5, 1951 and having the same title as the present application, which isrestricted to vapor phase reduction as distinguished from liquid phasereduction, to which the present application is limited. The gases maypass, as shown in both Figs. l and 2, through a suitable passage meansS4 to a condenser or condensing zone 55. This condenser may be suppliedwith suitable heat absorbing duid, passing into and out of the condenserthrough suitable passages 56 and 57 in a conventional manner. As shown,the condenser 55 may be constructed in a manner similar to a waste-heatboiler with the heat removed therefrom, for example, in the form of lowpressure steam, which may be used as process steam at any place wheresuch steam is desirable. Condensed liquid ferrous chloride may pass fromthc condenser or the condensing zone 55 through a passage 53 to aferrous chloride liquid storage chamber generally indicated at 59.Suitable means may be provided in conjunction with this storage chamberfor maintaining this ferrous chloride in liquid form and at atemperature at which it is desired to be used in the reducing Zoneportion of the process.

As set forth above, it may be desired to use a sweep gas passing throughthe vaporizing zone, shown as the vaporizer 36. Any inert gas may beused for this purpose. Nitrogen is a desired inert gas for use in thisrespect. As shown, there is a cycle for the recirculation of thisnitrogen or inert gas, including a passage or conduit 60, and a conduit61 communicating therewith. A suitable pump 62 may be inserted forinsuring the circulation of the inert gas. The conduit 60 communicateswith the tube 39 of the vaporizer 36. The inert gas ilows from thevaporizer along with the vaporized ferrous chloride through the passagemeans 5'4, thence from the condenser 55 with the liquid ferrous chlorideto the liquid storage chamber 59. At this point, the gas may beseparated from the liquid and pass out of the chamber 59 from the spaceabove the liquid therein through the pipe 61 to be recirculated by thepump 62. Any make-up nitrogen, or other inert gas, required tocompensate for leakage losses or otherwise, may be introduced into thecycle through a suitable branch pipe 63 under control of a valve 64.

The liquid ferrous chloride from the chamber 59 is conducted undercontrol of a valve 65 to a reducing zone and is there reduced by the useof a reducing gas, which has as its active reducing ingredient,hydrogen. This reduction reaction and the apparatus in which it iseffected is disclosed in greater detail in the copending application ofDarner et al., Serial No. 188,128, led October 3, 1950, now Patent No.2,664,352, issued Dec. 29, 1953, and entitled Process and Apparatus forReducing Ferrous Chloride in Liquid Form to Elemental Iron. The nozzlethrough which ferrous chloride may be introduced into the reducing zonemay further be that particularly illustrated and described in thecopending application of Walters, Serial No. 190,520, iled October 17,1950, now Patent No. 2,645,527, issued July 14, 1953,

and entitled Nozzle Construction. In general, however, liquid ferrouschloride is introduced into the reducing zone, here showndiagrammatically as an apparatus 66, through a suitable nozzle; andhydrogen is separately introduced into the reducing zone. In a preferredembodiment of the invention, as particularly disclosed in the Darner etal. application aforesaid, premature contact between the liquid ferrouschloride and the hydrogen is prevented by the use of a shielding gas,which may be an inert gas such as nitrogen. The use of the process ofDarner et al. and the apparatus particularly disclosed therein is to beconsidered within the purview of the present invention. The presentinvention may also employ the nozzle construction particularlyillustrated and described in the Walters application aforesaid.

In general, the reducing reaction is carried on to a substantial extent,but rarely to 100% completion, notwithstanding the normal use of anexcess amount of hydrogen over and above the stoichiometric equivalentof the ferrous chloride supplied to the reducing zone. As a result,there will be produced in the reducing zone as products of the reductionreaction therein, a substantial amount of solid powdered iron, and someferrous chloride which has not been reduced because the reaction tendsto proceed to an intermediate equilibrium rather than going to 100%completion. There will also remain in the gases, a substantial amount ofhydrogen, which has not reacted with ferrous chloride and the hydrogensupplied in excess of that necessary for reaction, also any nitrogen orother inert gas supplied to the process along with the hydrogen, plussuch gas supplied as a shielding gas to prevent premature contactbetween hydrogen and ferrous chloride aforesaid, HC1 produced as aproduct of the process of reducing the ferrous chloride with hydrogen,and possibly some additional inert gas as water vapor. All thesematerials pass from the reducer 66 or reducing zone through a suitablepassage indicated at 67 to a separator hereinafter described.

In Fig. 6, there is illustrated in slightly greater detail an apparatuswhich can be used for the apparatus shown generally in Figs. l and 2 at66. Referring now to Fig. 6, there is illustrated a substantiallyvertically disposed cylindrical chamber provided in a hollow cylindricalmember 68. Liquid ferrous chloride may be supplied to this chamberthrough a conduit 69 corresponding to the valved passage shown in Figs.l and 2, and including the valve 65. The reducing gas, including orconsisting of hydrogen, may be supplied to the chamber forming member 68through a conduit 70; and products of the reaction may be removed fromthe chamber forming member 68 through a passage or conduit 71. In orderthat the materials within the reducing zone, i. e. within the chamberforming member 68, may be maintained at a desired temperature, andparticularly for preventing heat loss through the walls of this chamber,the entire chamber may, if desired, be enclosed within a suitablefurnace 72, to which heat may be supplied by a plurality of fluid fuelburners 73 of any usual or desired type. The supply of fluid fuel tothese burners may be from a single pipe 713 under control of a suitablevalve 75. The products of combustion may pass from the furnace through asuitable stack under control of a damper therein as shown.

The products resulting from the reaction in the reducing zone may thenbe treated in either of two ways: (a) by hot separation in accordancewith the cycle illustrated in Fig. l; or (b) by cold separation inaccordance with the cycle illustrated in Fig. 2. In either case, theiron produced is eventually separated from the other products and is theprincipal product of the entire process.

Turning now to the Fig. l form of the invention including hotseparation, the products resulting from the reaction in the reducer orreducing zone are introduced as aforesaid into a separator 76. Thisseparator may take any desired form, the details of which are per se nopart of the present invention.

In the present instance, however, when hot separation is to be carriedon, a different type of separator is required from that disclosed in mycopending application, Serial No. 224,770 aforesaid, in that there isrequired to be supplied sufcient heat, so as to vaporize any ferrouschloride which may pass into the separator 76 in either liquid or solidform. For this purpose the separator may include a heating chamber whichmay take the form of an annular jacket or a series of tubes, or both,and through which` a heating fluid is supplied from a suitable sourcethereof, for example, through an inlet 77 and an outlet 78. Once theferrous chloride is Vaporized, the only solid material left will be themetallic iron powder produced, which may be separated from the othermaterials, all of which are gaseous, by any suitable method, forexample, that employed in conventional cyclone separators.

The metallic iron produced is collected in the conical lower portion ofthe separator 76 and may be removed therefrom through a passage 79having spaced valves 80 therein. As the separation is effected while thegases are hot, any ferrous chloride passing to the separator 76 in anyphysical state, will pass therefrom as a gas, mixed with unreactedhydrogen and with the HCl produced by the reaction in the reducing zone.In addition to this, there may be inert gases, such as nitrogen, whichmay be supplied as aforesaid into the reducing zone. These gases thenpass through a passage 81 into the last stage or portion of thechloridizing zone here shown as the chloridizer 17. in the preferredform of the present invention, the chloridizing gases are those derivedfrom the separation of the solid material following the reducing actionin the reducing zone. Means (not shown) are preferably provided forretaining these gases hot, so that heat loss is minimized and so thatcondensation of ferrous chloride in the lines is effectively prevented.This also serves as a method of introducing a substantial amount of heatinto the chloridizing zone. In the chloridizing zone, due to the lowertemperatures therein in respect to those in the reducing zone, anyferrous chloride present will be condensed, so as to pass out of thechloridizing zone as a solid along with ferrous chloride produced inthat Zone. The remaining gases will supply the gases required to bepresent in the chloridizing zone as aforesaid. In the event that it isnecessary to supply additional HCl to the cycle, this gas may besupplied from any suitable source thereof to the gases passing betweenthe separator and the chloridizing zone, i. e., to the passage 81. Suchmake-up HCl may be introduced through a pipe 82 connected to the pipe 3land provided with a suitable valve (as shown).

In completing the cycle, the only portion thereof which has not beenfully explained is the disposition of gases leaving the chloridizingzone. These gases will contain some hydrogen, which has not been used inreducing iron oxide and which it is desired to recirculate, water vaporproduced in the chioridizing zone by the reaction between hydrogen andiron oxide and between HC1 and iron oxide, and also any water vaporintroduced as moisture in the raw material, and any unreacted HCl. Theremay also be present more or less inert gas. These mixed gases are thenpreferably cooled and scrubbed in a suitable scrubbing device generallyindicated at 83. For this purpose, these gases may be passed through aspray chamber through which cold water is supplied through a passage 34.The function of this scrubbing device is to condense out a large portionof the water vapor, and also to remove from the gas substantially allthe HCl, which will pass out of the scrubber in the waste water as anHCl solution. This waste water including the dissolved HCl passes out,as shown, through a pipe 85. If the concentration of HC1 in this wastewater were suficiently high, it could be recovered therefrom by meansknown to the art and which per se form no part of the present invention.The gases leaving the scrubbing device 83 pass through a pipe S6 enroute to the reducing zone.

As an inert gas, such as nitrogen, is supplied to the rcducing zone asaforesaid, it is necessary to bleed out and waste some of therecirculating gases, so as to prevent the building up of theconcentration of the inert gas in the recirculating gases to anundesired high value. This bleeding of gases may be done either beforeor after passing the gases through the scrubbing device 83. In the eventthat it is desired to recover HC1 from the gases, this bleed out pointis preferably located after the scrubbing device. However, it isnormally the desired practice to use a maximum of the HCl in thechloridizing zone, so that the amount thereof in the gases leaving thiszone is quite small and a bleeding of excess gases in advance of thescrubbing device may be effected, Under these conditions, the small lossof HC1 in the gases bled out of the recirculation is compensated for bythe smaller total amount of gases which remain to be treated in thescrubbing device S3. As shown, a branch pipe S7 is provided, ow throughwhich is controlled by a valve 88, the gases being discharged to theatmosphere or disposed of in any desired manner.

source of hydrogen (not shown) to the pipe $6 and provided with asuitable valve 91, by which the hydrogen being supplied to the systemmay be controlled. in order to determine and control the ow of gas andparticularly the rate of supply of hydrogen to the reducing zone, a

iiow meter generally indicated at 92 is preferably interposed in thepipe 86 between the make-up hydrogen branch pipe 90 and the reducer 66.The pipe 36 leads to the reducer as shown in Figs. l and 2 andcommunicates with the pipe 70 shown in Fig. 6, if that form of thereducer is employed.

Turning now to the Fig. 2 form of the invention in which cold separationis employed, effective on the products leaving the reducing zone, suchproducts are shown passing from the reducer 66 through a pipe 67 to acold separator 93, in which these gases are cooled at least to atemperature such that any ferrous chloride present will be condensed tosolid form. For this purpose, the separator 93 may be formed in a mannersimilar to the separator 76 except that a cooling medium may be passedthrough an inlet 94 and an outlet 95 thereof, so as to effect thedesired solidication of any ferrous chloride supplied to this separator.Thus, both the iron and the ferrous chloride will be solid in theseparator 93 and may be separated therein from the remaining gases. Theremaining gases may then pass through the pipe 81 to the chloridizingzone as described in connection with the Fig. l form of the invention,being augmented as may be necessary by malte-up HCl through the branchpipe 82 under control of the valve therein.

Solid materials from the separator 93, which consists essentially ofmetallic iron and uureduced ferrous chloride, may then be passed fromthe separator under suitable control (not shown) to a recovery system,by which the iron may be separated from the ferrous chloride, so thatboth may be used as desired. One such system is indicateddiagrammatically in Fig. 2 as including a leaching bath 96, in which theferrous chloride may be dis solved in a suitable solvent. This solventmay be water, with suitable provisions being made to prevent undesiredrusting of the iron. The undissolved iron may then be separated from thesolution of ferrous chloride in a suitable separating means, such as afilter 97, and the iron passed to a suitable point where it may be used.The solution may then be evaporated to leave the ferrous chloride, whichmay be used for any desired purpose, includ* ing admixing it with theraw material introduced into the chloridizing zone, so that it may thusbe returned to the process. Alternatively, this ferrous chloride may beused for any other purpose for which it is adapted. ln the event thatsome relatively expensive solvent is used in the leaching bath 96, suchas one or more of the organic solvents, it may be desired to save thesolvent and recycle it to the leaching bath through a passage 93 inwhich a pump 99 is interposed. The details of this leaching and solventextraction process form per se no part of the present invention and maybe replaced by equivalent apparatus of any desired type. With thisexception, the cycle illustrated in Fig. 2 may be essentially the sameas in Fig. l, so that the various common elements are indicated by thesame reference characters.

The cycle as to some of the materials employed, which has been explainedin considerable detail as to the several apparatus elements used in theprocess, must be coordinated together in practice, so that there will bea balance effected throughout all the operations.

The process is preferably primarily controlled by controlling the rateof supply of liquid ferrous chloride to the reducer 66 from the supplyor storage chamber 59. In this respect, the present process differssomewhat from the process of my copending application, Ser. No. 224,770.ln view of the control being effected at this point, it is no longernecessary that there be a storage means provided as shown by the hopper33, or equivalent storage point for the solid chloridized material; butthis material could be fed directly from the chloridizer 17 to thevaporizer 36. In any event, the operation of vaporization of thechloridizing zone.

the ferrous chloride is necessary to be accomplished only at such a rateas to provide an ample supply of liquid ferrous chloride in the chamberS9. Thus, the vaporizer is normally operated at the same rate as that atwhich the raw material used is chloridized, so that the storage chamberor hopper 33 is useful only by reason of convenience in materialhandling and is not a necessary storage point in the process. As in mycopending application, it is preferred to use a flash type of vaporizingin the vaporizer 36, so that the vaporization may proceed at the sainerate that chloridized material is supplied to the vaporizer.

if then the rate of supply of hydrogen to the reducing zone is carefullycontrolled by controlling the amount of make-up hydrogen admittedthrough the pipe 90 by the valve 91, with the rate of supply of thegases indicated by the reading of the flow meter 92, the reaction withinthe reducing zone may be carefully and properly controlled. This, inturn, will control the amount of HCl produced in the reducing zone. Thisamount of HC1, coupled with the amount of make-up HC1 introduced intothe system through the pipe 82. under control of the valve therein, willcontrol the amount of HCl introduced into This amount of HCl can then bebalanced by the amount of raw material supplied to the chloridizing zoneunder control of the variable speed motor 14. Thus, there is required inthe entire system to assure a balance throughout, only one intermediatestorage point, namely, the storage chamber 59 for the liquid ferrouschloride. With this one storage point, it is possible to effect accuratecontrol of all the elements of the system and of the recirculationstherein.

Another interlocking arrangement in the process, which is necessary tobe provided in order that the process as a whole shall be effective, isin connection with the hot separation cycle disclosed in Fig. l. lf thegases passing from the separator through the pipe 8l to the chloridizingzone are at a temperature higher than about l250 F., ferrous chloridecontained as a vapor in these gases may tend to condense as a liquid inthe chloridizing zone, rather than as a solid; and also these highlyheated gases will tend to melt the ferrous chloride produced in thechloridizing zone upon their initial contact therewith. Any moltenferrous chloride in the chloridizing zone will tend to agglomerate withthe rest of the solid materials in this zone and will prevent a desired,substantially free flow of these materials through the chloridizingzone. This will also result in hindering chloridization by mechanicallymasking the unchloridized material and preventing contact between it andthe chloridizing gases. As a result and in order to avoid all thesediiculties, it is practically necessary that the gases being supplied tothe chloridizing zone be at a temperature below about l250 F., andpreferably, in order to conserve heat, be almost up to this temperature,such as about l200 F. Under these circumstances, due to the partialpressures of the other gases present, ferrous chloride will not condenseout in the pipe 81, but will condense out in the chloridizer as a solid,rather than as a liquid.

There follows examples illustrative of the various conditions underwhich the process of the invention may be practiced and of theinterrelation of the several steps of the process. In these examples7the quantities given throughout are based on the production of one tonof iron powder in order that there may be a uniform basis for comparisonof the various conditions as set forth.

Example I This example illustrates the conditions under which theprocess is practiced when the reduction step is carried out in such amanner as to produce an exhaust gas, used directly and as such forchloridizing and containing a relatively low HCl content, i. e., about2% by volume.

For each ton of iron powder produced, 8800 lbs. of Tobin Formation oreare fed into the chloridizing zone. This ore has the following averageanalysis:

Per cent Ignition loss 4.1 Gangue 49.3 FesOs 46.6

The ore is fed into the cold end of the chloridizing zone at atemperature of about 300 F. to prevent condensation of water vapor andHCl in the vapor. The ore moves through the chloridizing zonecountercurrent to the stream of chloridizing gas and is gradually raisedin temperature to about 900 F. Because of the relatively high percentageof hydrogen in the chloridizing gas, it is necessary to keep thetemperature of the solid material in the chloridizer below about 950 F.in order to prevent reduction of the FeClz formed to metallic iron atthis time.

The chloridizing gas which is recycled directly from the reducing zone,has a composition of about 0.5% FeClz vapor (based upon hot separationas described in connection with Fig. 1), 48.5% H2, 1.0% HC1 and 50% N2all by volume. Since one-half of the volume of this chloridizing gasconsists of inert nitrogen, it can be considered that HCl makes up about2% by volume of the active chloridizing gas entering the chloridizingzone. For each ton of iron produced the amounts of gas entering thechloridizing zone are: 460 lbs. FeClz, 2900 lbs. HC1, 6900 lbs. H2 and101,000 lbs. N2. This includes about 265 lbs. make up HC1.

During its passage through the chloridizing zone the Fe2Os in the ore ischloridized to the extent of about 70%, thus producing 10,140 lbs. ofchloridized ore per ton of iron produced. This chloridized ore, togetherwith about 460 lbs. FeClz, which has condensed from the chloridizing gasin the chloridizing zone, is passed to a vaporizing zone, where thetemperature is raised to about 1750 F. In order to accomplish thisvaporization, a stream of nitrogen is passed through the vaporizing zonewhich may be at the rate of about 1110 lbs. of nitrogen per ton ofpowdered iron produced. By this operation 5,020 lbs. of FeClz vapor areproduced and there is left in the vaporization zone 5,120 lbs. of gangueto be discharged. This FeClz vapor is then passed to a condenser whereit is cooled to a temperature of about l300 F. and thereby condensed toa liquid. From the condenser the FeClz liquid is passed to a storagetank and the nitrogen is drawn oif from the space above the liquid andrecycled into the vaporizer.

ln the chloridizing zone, the gas stream loses over 90% of its HC1 andsome of its hydrogen content, while picking up water vapor from themoisture content of the ore and from the products of the reduction andchloridizing reactions. The resulting exhaust gas from the chloridizingzone contains, per ton of iron produced, about 265 lbs. of HC1, 1,020lbs. water vapor, 6,900 lbs. of H2 and 101,000 lbs. of nitrogen. Aportion of this gas is then bled out of the system amounting, on thebasis of each ton of powdered iron produced, to about 1.5 lbs. of HCl,7.5 lbs. of water vapor, 37.5 lbs. of hydrogen and 550 lbs. of nitrogen.The gas stream from which this exhaust gas has been taken is then passedthrough a scrubbing zone, wherein substantially all of the HCl and watervapor content are removed, leaving a substantially dry gas con sisting,per ton of powdered iron produced, of about 100,450 lbs. of nitrogen and6,850 lbs. of hydrogen. To this gaseous stream, about 152 lbs. ofmake-up hydrogen are added and the resultant mixture passed into thereducing zone. This gas contains about 25% nitrogen and 48% hydrogen byVolume. When the FeClz liquid is introduced into the reducing zone inthe amount stated vso y14 reduction of the FeClz formed to metallic ironat this point, since the hydrogen content of the chloridizing gas isstill relatively high. l

The chloridizing gas leaving the reducing zone has a composition ofabout 0.7% FeClz, 2.5% of HC1, 46.8% of hydrogen and of nitrogen, all byvolume. Thus with respect to the active ingredients, the HC1 representsabout 5% of the total volume. For each ton of iron produced, the weightsof the several gases entering the chloridizing zone are: 270 lbs. FeClz,2,750 lbs. of HC1, 2,750 lbs. of hydrogen and 40,500 lbs. of nitrogen.This includes about 105 lbs. of HCl added as a make-up.

During its passage through the chloridizing zone, the Fe203 ischloridized to an extent of about 85%, thus producing 8,640 lbs. ofchloridized ore per ton of iron produced. This chloridized ore, togetherwith 270 lbs. or FeClz, which is condensed from the chloridizing gas inthe chloridizing zone (again using the Fig. 1, hot separation form ofthe process), is passed to a vaporizing zone where its temperature israised to about 1,750 F. and a gas stream of about 1,060 lbs. ofnitrogen per ton of metallic iron produced is passed over the surface ofthe chloridized ore as a carrier or sweep gas. This drives olf 4,830lbs. of FeClz vapor and leaves behind 4,080 lbs. of gangue to bedischarged. The FeClz vapor is then passed to a cooling zone, where itis condensed to liquid FeClz at a temperature of about 1300 F. Thisliquid is then passed to and through a storage tank; and about 1,060lbs. of nitrogen are drawn oil? from the space above the liquid surfaceand recycled as a sweep gas into the vaporizing zone. In thechloridizing zone, the chloridizing gas loses most of its HCl contentand some of its hydrogen content, so that for each ton of metallic ironproduced, the gas leaving the chloridizing zone contains about 105 lbs.of HC1, 1,020 lbs. of water vapor, 2,720 lbs. of hydrogen and 40,500lbs. of nitrogen.

After leaving the chloridizing zone, a portion of the gas stream is bledoff in order to prevent the building up of too much nitrogen in thesystem; and during the course of this bleeding operation, the gas streamloses about 1.5 lbs. of HC1, 17.5 lbs. of water vapor, 35.5 lbs. ofhydrogen and 530 lbs. of nitrogen. The remaining gas is then passedthrough the scrubbing zone, Where substantially all of the HC1 and waterVapor contained are removed, so that a dry gas consisting substantiallyof about 45% hydrogen and 55% nitrogen by volume leaves the scrubbingzone. To this dried gas is added about 150 lbs. of make-up hydrogen perton of metallic iron produced, so that the reducing gas entering thereducing zone (5,020 lbs.), a quantity of nitrogen used as a shield gasI around the nozzle amounting to about 555 lbs. of nitrogen per ton ofiron powder produced is introduced into the system. The hydrogen andliquid FeClz introduced in these proportions into the reducing zone andmaintained at a temperature of about 1250 F. react in such a manner thatabout 91% of the FeCl2 is reduced to metallic iron. After separationfrom the metallic iron, the exhaust gases, having the composition setforth above, are recycled to the chloridizing zone.

Example II this example, about 85% of the iron values of the TobinFormation ore (the same as in Example l) are converted to FeClz, so thatin this case only 7,240 lbs. of ore need be introduced into thechloridizing zone per ton of powdered iron produced. It is necessaryunder these circumstances, to keep the temperature of the solid materialof :l

the chloridizer below about 1050 F. in order to prevent contains, perton of metallic iron produced, about 39,970 lbs. of nitrogen and 2,820lbs. of hydrogen. In addition to the nitrogen contained in the reducinggas, about 530 lbs. of additional nitrogen are introduced into thereducing zone in the form of a shield gas, introduced around the nozzlethrough which the liquid FeClz is introduced. The hydrogen and FeClzintroduced in these proportions in the reduction zone and maintained ata temperature of 1250 F. are reacted in such a manner that about 94.5%of the FeCl2 is reduced to metallic iron. After separation from themetallic iron, the exhaust gases having the composition set forth above,are recycled to the chloridizing zone.

Example III This example illustrates the operation of the process whenthe reduction of the liquid ferrous chloride is carried out in such amanner as to produce exhaust gas from the reducing zone, the activeingredients of which contain about 15% HC1. As in the previous example,7,240 lbs. of Tobin ore of the composition given in Example l isintroduced into the chloridizing zone for each ton of metallic ironproduced. Because of the lower hydrogen concentration of thechloridizing gas, it is now possible to raise the temperature in thevhotend of the chloridizing zone to about 1200 F. without the formation ofmetallic iron produced by the reduction of solid FeClz. However, at thistemperature, certain mechanical diiculties begin to be encountered dueto the agglomeration of the solid material. Thus, 1200 F. appears to beabout the maximum practical temperature at which the hot end of thechloridizing zone can be maintained. As a result of this highertemperature limit, it is possible to chloridize still more rapidly thanunder the conditions described ,in either of the two preceding examples.

The chloridizing gases as recycled from the reducing zone contain about0.4% of FeClz vapor, 7.5% HC1,

15 42.1% of hydrogen and 50% of nitrogen, all by volume. Thus, for eachton of metallic iron produced, there is fed into the chloridizing zoneabout 490 lbs. of FeCl2 vapor, 2,640 lbs. of HCl (including about 33lbs. of make-up HC1), 810 lbs. of hydrogen and 13,420 lbs. of nitrogen.

During its passage through the chloridizing zone the FezOa in the ore ischloridized t-o the extent of about 85 thus producing about 8,640 lbs.of chloridized ore per ton of iron produced. This chloridized ore,together With about 490 libs. of FeClz, which has condensed from thechloridizing gas in the chloridizing zone, is passed to a vaporizingzone where the temperature is raised to about 1750 F. In order tofacilitate this vaporization, a stream of nitrogen is passed through thevaporizing zone at the rate of about 1,120 lbs. of nitrogen per ton ofiron produced. By this operation about 5,050 lbs. of FeClz vapor isproduced and there is left in the vaporizingzone 4,080 lbs. of gangue tobe discharged. This FeCl2 vapor is then passed to the condenser where itis cooled to a temperature of about 1300 F. to form liquid FeClz. Fromthe condenser this liquid is passed to a storage tank and 1,120 lbs. ofnitrogen are drawn off from the space above the liquid and recycled tothe vaporizer for reuse as a sweep gas.

`In the chloridizing zone, the gas stream loses practically all of itsHC1 content and a small portion of its hydrogen content, While pickingup water vapor from the products of the reaction and from the moisturecontent of the ore. The resulting gas leaving the chloridizing zonecontains, per ton of iron produced, about 33 lbs. of HCl, 775 lbs. ofhydrogen, 1,020 lbs. of water vapor and 13,420 lbs. of` nitrogen.

About of the volume of this exhaust gas is then bled out of the systemin order to prevent excessive buildup of nitrogen; and the resulting gasstream is then passed through a scrubbing zone, wherein it losessubstantially all its water and HC1 content. The content of the gasstream leaving this scrubbing zone contains, per ton of metallic ironproduced, about 740 lbs. of hydrogen and 12,850 lbs. of nitrogen. Tothis gas is added about 147 lbs. of make-up hydrogen, so Athat the gasentering the reducer contains about 887 lbs. of hydrogen and 12,850 lbs.of nitrogen. At the same time about 555 lbs. of nitrogen is introducedthrough the nozzle in the reducing zone along with the FeClz liquid,this nitrogen serving as a shielding gas. FeClz liquid and hydrogenreact in these proportions at the temperature of the reducing zone,namely about 1250 F. t-o etect a reduction of about 90% of the FeClz tometallic iron. After separation from the metallic iron, the exhaustgases, having the composition set forth above, are recycled to thechloridizing zone.

Example IV This example illustrates the operation of the process whenthe reducing cycle is carried out under conditions similar to those ofExample III above, but wherein the circuit carries a recycled load ofabout half as much nitrogen as previously, so that the chloridizing gasrecycled from the reducing zone contains only about 25 nitrogen byvolume. The operation of the process is much the same as that describedin Example Ill above, except that the composition of the gases leavingthe reducing zone is about 0.6% FeClz, 11.2% of HCl, 67.2% of hydrogenand 25% of nitrogen, all by volume. Thus, of the active -components ofthis gas, about of the content by volume is HCl. The chloridizing steptakes place somewhat more eiciently at this low concentration ofnitrogen and only about 21.5 lbs. of make-up HCl need be added to thesystem per ton of metallic iron produced, Whereas 33 lbs. of make-up HC1were required when operating the system with the higher nitrogen contentin accordance with Example III.

Example V When the process is operated with a higher nitrogen recycledload, but with the same ratio of HC1 to hydrogen, as illustrated inExamples lll and IV above, the operation of the cycle is much the same,except that a greater loss of HC1 occurs in the chlorodizing system and,consequently, a greater amount of make-up .HC1 ymust be added to theexhaust gas :from the reducing zone. Thus, when operating underconditions in which a recycled load of nitrogen is employed of aboutthree times as much as that illustrated by Example IV, the exhaust gasesleaving the reducing zone have a content of about 0.2% of 16 FeClz,3.75% of HCl, 21.05% of H2, and 75% of nitrogen, all by volume. Theactive ingredients of this gas still contain about 1,5% HCl, with thebalance hydrogen. The total amount of nitrogen recirculated through thesystem under these conditions is about 40,400 lbs. per ton of metalliciron produced.

Using the exhaust gas of the composition set forth above, it is foundnecessary to add about 67.5 lbs. of make-up HCl to the system, per tonof metallic iron produced, as compared with correspondingly smalleramounts, such as 33 and 21.5 lbs. necessary when operating under theconditions set forth in Examples III and lV, respectively. This appearsto be due to the larger quantity of gases passed through thechloridizer. The chloridizing gas is in the chloridizing zone a shortertime and has less chance of utilizing the last traces of HCl.

Example VI This example illustrates the method of operating the processwhen the reduction of the liquid FeClz is carried out in such a manneras to produce an exhaust gas for chloridizing containing about 25% HCl,by volume of the active ingredients in this gas. When operating in thismanner, 7,240 lbs. of Tobin ore of the composition given in Example lare introduced into the chloridizing zone, per ton of powdered ironproduced.

The chloridizing gas leaving the reducing zone has a composition ofabout 2.5% of FeClz, 35% of hydrogen, 12.5% of HC1 and 50.0% ofnitrogen, all by volume. Thus, with respect to the active ingredients,the HC1 is about 25% of the total volume. For each ton of metallic ironproduced, the gases entering the chloridizing zone amount to about 1,930lbs. of FeClz, 2,660 lbs. of HCl, including 20 lbs. of make-up HC1, 361lbs. of hydrogen and 8,100 lbs. of nitrogen.

During its passage through the chloridizing zone, the FezOa in the oreis chloridized to the extent of about as described in the previousexamples. Because of the greater amount of the FeClz condensed in thechloridizing zone from the exhaust gases from the reducing zone, a totalof about 6,490 lbs. of liquid FeClz are thus obtained from the passageof 7,240 lbs. of ore through the chloridizing zone. The FeCl2 liquid isobtained by vaporizing the FeClz from the chloridized ore and condensingit to a liquid, as previously described.

ln the chloridizing zone the chloridizing gas loses most of its HC1content, together with some hydrogen, so that the gases leaving thechloridizing zone contain, for each ton of metallic iron produced, about20 lbs. of HC1, 325 lbs. of hydrogen, 1,020 lbs. of Water vapor, whichhas been picked up from the products of the chloridizing reaction, and8,100 lbs. of nitrogen.

After leaving the chloridizing zone, about 10% by volume of this gas .isbled off to prevent the building up of too much nitrogen in the system.The remaining exhaust gas from the chloridizing zone is passed through ascrubbing Zone Where the Waterand HC1 contents thereof are substantiallyremoved, leaving a relatively dry gas containing, per ton of metalliciron produced, about 330 lbs. of hydrogen and 7,380 lbs. of nitrogen. Tothis gas stream are added about lbs. of make-up hydrogen, while anadditional 710 lbs. of nitrogen are introduced into the reducing zone asa shield gas around the jet of FeClz liquid. When the temperature in thereducing zone is maintained at about 1250o F. and the hydrogen andnitrogen are reacted in these proportions, the efficiency of reductionof FeClz to metallic iron is only about 71%. After separation from themetallic iron, the exhaust gases having a composition set forth above,are recycled to the chloridizing zone.

Example VII This example illustrates the method of operating the processwhen the reduction of ferrous chloride vapor is carried out in such amanner as to produce an exhaust gas for chloridizing containing about35% HCl by volume. When operating in this manner, 7,240 lbs. of Tobinore of the composition given in Example I are introduced into thechloridizing zone for each ton of metallic iron produced. The reductionoperation is relatively inefficient in this instance as in order toproduce a gas having such a Vrelatively high HCl content, the exhaustgas from the reducer is rrelatively rich in unreacted FeClz.` Theexhaust jgas from the .reducing zone contains about 14.75% of FeClz,17.5% of HC1, 17.75% of hydrogen and-`50:0%2'1'of nitrogen;allfbyfvo'lunie.'A T hus the'content of; the activechloridizngingredientsf'of this gas, namely, hydrogen 'and HC1, is'abouty 35% HC1 and 65% hydrogen, by' volume. On the` vbasis of. eachtonv metallic iron produced, there' is introduced'into the chloridizingzone about-l 7,7005 lbs; of.l FeCI2`,.;2`,65O\lbs. of. HC1, .148 lbs; ofhydrogen and 5,750'lb's. of nitrogen. The gases leaving the chloridizingzone contain about 11.5 lbs. of HCl, 105y lbs. of hydrogen, 1,020' lbs.of water vapor. and 5,750- lbs. of nitrogen. After about 25% .of thevolume of'this exhaust gas is1bledout"`of the: systeml to preventbuild-up fofY excessive amounts of nitrogen, thegas is 'passedtoai'scrubbing zone, .wherein' substantially allthe water :vapor' and: HC1content are Iremoved. .The relativelyA dry-"gasaleavingy 'ther scrub'-bing zone. thenv contains aboutrSO-'llbs of hydrogen-fand 4,400 lbspofnitrogen, lper -tonof'metallic ironfproduced: Toy this mixture about1401.1bs;oflmakempfrhydrogen are added. ln addition, about'. 1,350'lbs'.of nitrogen arefintroduced` into. the reducing zone-nasa shield gasfor-:theliquid` FeClz jet.-

BecauseY of .they .high' HC1'. content'iof thei clrlo'ridizing gas, `alarge amount .of ferrous lchlorideitis nowi con'- densedin the`chloridizing zone, so.` that for. eachton ofrironproduced, about` 12,260lbs. 'of ferrouschloride liquid; are f now passed. into a .the:.reducingl zone :per ton of'fmetallic f iron, produced.-` When. .theFeCla'. and: hydro; gen are reacted: in thesefzproportions,atrthentemperalturezof `12507 F.,`. the reduction reactioniis'onl'ysabout 35.5% eflicient;-

After separation from# the .metallic; iron, .-thei exhaust gases..fromthe reducingv zone.;.havingifthetfcomposition set for-.th iabove',4 are.recycledfto the lchloridizi-ng zone :i

While several. embodiments offthe :inventionrhave been disclosedt inthe., specification; and' drawings an'dfhave been illustratedin YtheVexamples .,given'; itl '.Willf-.be milder;A stood thatgthe.processrmayfbef furtherf'varied.: aszwill occurntovthose-.skilledin.the;art1 from the foregoing: dis4 closure.r Theappendedclaims.. are to ben-consid'el'ed as embracing f such:equivalentsl wherever-x. thisA is :inotfi pre'- cluded .byexpressed-:limitations therein.

What is claimed'is:v f

1. The process of preparingfmetallic iron fromlfa solid: ironoxidefcontaining; material;'comprisingfthe steps ofchloridizing a.substantialxproportion of :theuiron oxide ofsaid material to formferrouschloridetzby'f'com tacting'- said.solidfmaterialin'achloridizingszone and at atemperatureof lat leastn500"Y F. butbelowrthesfmelte ing point; of said ferrous* chloridewitlrzagaseouszmixf' ture containing, as essential= ingredients, HG1n and: hy#ydrogen-and wherein thefHCl concentration'fis from about to labout l25%.by'volume based. upon-thetotaly of hydrogen plus HClin,said. gaseousmixture, and pree venting, the reduction of iron tothe@ metallic...stateby keeping said temperature always belowftheflimitinrea spect 1 to yHC1concentration as-.definedcin.thefffollowing table.: passing..A the`remaining solid material-f as.- .thus

Temperature 1imit;( F.)

below which temperature must.b ..v maintained` HC1 fconcentration, ptcxbby volume basedi on` C1 about 5.

and over chloridized from said chloridizing zoneto 'a vaporizing zone,and-there raising the'temperature `thereofy suf-1 cientlyt to vvaporizethev ferrous chloride content fof; this material; separatingthefvaporized ferrouschloridel produced in said vaporizing zonefrom-the. non-volatile material therein,- and passing thevaporizedferrous chloride into a condensing zone; condensing thevaporizedfrrouschloride in said condensing zone to form liquid ferrous chloride vbyabstracting heat therefrom; introducingvthediquid ferrous chloride thusproduced into a reducing zone-as a iinel-liquidpspray, separately' introducinginto said reducing zone a Vgaseous medium, the essential activereducing ingredient of which is hydrogenyforreaction with the ferrouschloride droplets of said spray, so as to reduce at least a substantialportion taining the *temperature in saidreducing zone at least ashigh-as' the meltingpomtcf ferrous chloride?butbe low'7 theimelfingpoint ofv'vsad metallic iron; separating the products resulting from`the reactionin sai'd'redu'cring'y zonebetween said gaseous medium`including hydrogen' and the liquid ferrous chloride droplets', intosolid material including the metallic ironand (b.) .ga's couslmaterials; including make-up lH Cl in said gaseous materials in amount@required' to providejthe aforesaid relative'p'roportions of HC1andhydrogen in sa'id Chlo 'dfizing' step andI passing: therresultingga'seous materials tosaidt'chloridizing zone assaid gaseousmixture which is supplied to said chloridi'zing; zone' for yuse'asaforesaid; removingthe gaseous yproducts of' the', react-icuii; said'chloridiz'in'g.y zone froml such'y zone and `separating therefrom asubstantial amount of l water vapo content thereof, and-passingth'e'sefremaining' gase'srfrbmiwhich water vaporl'l'as been' removedAand togvvhich rn'alefup hydrogen is added, into'v said reducingzzonegassaid` gase'onsfmediurn whichis separately introducedinto' said reducingzone. l y

2 The processv in"a`ccordance with; claim11, wherein said gaseousmaterials ,resulting-y from said reaction b efjtween'y hydrogen andferrous chloride droplets insaid reducing'v zorreand which are passed tosaid, chjloridizfing1zone contain about-1,5%" of HCl by volumevv basedupon'the to'talof hydrogen andHCl. y ,i

3.1The-proces`s of'- preparing metallicv iron` from" a solidiironoxide-containing material, comprising the steps. ofchloridizing asubstantial proportion of the iron oxideof saidy material to' form.'ferrousuchlor'ide by contacting said solid material infa'chloridizingzone and ata temperature of at least 500 F. but below the melting-@pointof said ferrous chloride with a gaseous mixture containing; aslessentialu ingredientsg'-HCl" andhyl drogen and wherein ,the HC1,concentration isf from about 5% to about-25% by volume based upony'th'eto'tl of hydrogenvplus HClin said gaseous mixture,and-prevent-ingthe reduction of ironto the metallic'l state.,bykeepingf" saidtemperature always .below th`elimit-1iri respectto -HClconcentration Vas dened vinthe] following; table passing i theremainingI 'solid materials as thus Temperature limit F2),-`belo'mwbichf temperature 'i mustvbe maintained:

HG1 concentration, pclllt by volume based on chloridized ffrornA saidchloridizing zone to a jvaporizig zone",y and there "raisin'g' -thetemperature l thereof sufciently vto vap'orizel the'ferrous 'chloride'conten'twoi this'fimaterial;separatingfthe vaporized ferrous chlorideproduced: in said' vaporizing -zone fr'o m"`theKV non-volatile materialtherein,j and passing the vaporized ferrous chloride into a condensingzone; condensing the vapoiw' izedA ferrous'I chloride vin saidcondensing'zone to form liquidi ferrous chloride by abstrac'ting heattherefrom, and:V collecting vsaidy 1iquid"ferrous' chloride ini astoragel chamber thereforinv which the ferrous chlorideismainftained/'in the liquid: state; supplying liquid ferrouschlo ridefrom-said storage chamber to a reducing zone and introducinghitinto thereducing 1zone as affine liquid sprayg." separately introducing int saidreducing zone aj gas,'the essential active reducing-'ingredient ofwhich'is hydrogen; fory reaction with thefer'rous chloride,L drop letsof'lsaid spray, `so as to reduce' at leastfa substantialportion'ofthe'ferrous chloride to metallic iron, .while maintaining-thetemperature in said reducing'v zoneatv leastf'aslhigh as the'meltingpoint of ferrous [chlorideg'l butfbelowthe melting 'point ofvsaidinetallicY iron; sepr,` aratingtheproducts resulting fromthe'nreactionfinisaid reducing-zone between saidgas including hydrogenand? saidv -liquid ferrouschloride into` (a) solidmaterialfin-fcludingfthemetall'ic iron and (b)^ gaseous ,rmterialsf` includingmalte-upV I-IClv in saidf'gase'ous materialsy in amount-requiredtoprovi'de the aforesaid "relativeprf)-r portions of :HC1 and' hydrogenin said chloridizing' stepl and?!v passing Y the resulting" gaseousmaterials` to.-k saidj chloridiz-ing'zonefas vrsaid gaseous, mixturewhich is su plied to said chloridi'zin'gI 'zone`"for use as 'af,r'es'ai`d;

rem'ov ng the gaseous productsof. the reactionfin s aid passing theseremaining gases, from which water vapor Ahas been removed and to whichmake-up hydrogen is added, into said reducing zone as said gas which isseparately introduced into said reducing zone, and controlling andbalancing the operation of the several steps ofthe process aforesaid bycontrolling the rate at which liquid ferrous chloride is supplied fromsaid Storage chamber to said reducing zone, the rate of supply ofhydrogen to said reducing zone and the amount of make-up HCl included insaid gaseous materials passing to said chloridizing zone.

4. The process of continuously preparing metallic iron from a solid ironoxide-containing material, comprising the steps of continuouslychloridizing a substantial proportion of the iron oxide of said materialto form ferrous chloride by continuously contacting said solid materialin a chloridizing zone and at a temperature of at least 500 F. but belowthe melting point of said ferrous chloride with a gaseous mixturecontaining, as essential ingredients, HCl and hydrogen and wherein theHCl concentration is from about to about 25 by volume based upon thetotal of hydrogen plus HC1 in said gaseous mixture, and preventing thereduction of iron to the metallic state by keeping said temperaturealways below the limit in respect to HC1 concentration as defined in thefollowing table: continuously Temperature limit; F.) below whichtemperature must be maintained HC1 concentration, pzrlcit by volumebased on C1 about 5. 15 and over-.

passing the remaining solid material as thus chloridized from saidchloridizing zone to a vaporizing zone, and there continuously raisingthe temperature thereof sufticiently to Vaporize the ferrous chloridecontent of this material; continuously separating the vaporized ferrouschloride in said vaporizing zone from the non-volatile material therein,and continuously passing' the vaporized ferrous chloride into acondensing zone, continuously condensing the vaporized ferrous chloridein said condensing zone to form liquid ferrous chloride by abstractingheat therefrom; continuously introducing the liquid ferrous chloridethus produced into a reducing zone as a tine liquid spray, separatelyand continuously introducing into said reducing zone a gaseous medium,the essential active ingredient of which is hydrogen, for continuousreaction with the ferrous chloride droplets of said spray, so ascontinuously to reduce at least a substantial portion of the ferrouschloride to metallic iron, while maintaining the temperature in saidreducing zone at least as high as the melting point of ferrous chloride;but below the melting point of said metallic iron; continuouslyseparating the products from the reaction in said reducing zone betweensaid gas including hydrogen and the liquid ferrous chloride dropletsinto (a) solid material including the metallic iron and (b) gaseousmaterials; including make-up HCl in said gaseous materials in an amountrequired to provide the aforesaid relative proportions of HC1 andhydrogen in said chloridizing step and continuously passing theresulting gaseous materials to said chloridizing zone as said gaseousmixture which is continuously supplied to said chloridizing zone for useas aforesaid; continuously removing the gaseous products of the reactionin said chloridizing zone from said zone, continuously separatingtherefrom a substantial amount of the water content thereof, andcontinuously passing these remaining gases from which water vapor hasbeen removed and to which make-up hydrogen is continuously added intosaid reducing zone as said gaseous medium which is separately introducedinto said reducing zone, and controlling and balancing the operations ofthe several steps of the process by controlling the rate at which liquidferrous chloride is supplied to said reducing zone, the rate of supplyof hydrogen to said reducing zone and the amount of make-up HC1 includedin said gaseous materials passing to said chloridizing zone.

5. The process of preparing metallic iron from a solid ironoxide-containing material including some iron in a,t ri valent state,comprising the steps of converting a substantial proportion of the ironoxide of said material to ferrous chloride by substantially simultaneousreduction and chloridization by contacting said material, while passingit through a chloridizing zone, with a gaseous mixture containinghydrogen and HCl, and while progressively raising the temperature ofsaid material as it passes through said chloridizing zone from atemperature in the range of about 500 F. to about 800 F. to atemperature in the range of about 800 F. to about 1200" F. and whereinthe HC1 concentration is from about 5% to about 25% by volume based uponthe total of hydrogenplus HCl in said gaseous mixture, and preventingthe reduction of iron to the metallic state by keeping said temperaturealways below the limit in respect to HCl concentration as defined in thefollowing table: passing the remaining solid material as thuschloridized from said chloridizing zone to a vaporizing zone, and thereraising the temperature thereof sufficiently to vaporize the ferrouschloride content of this material; separating the vaporized ferrouschloride produced in said vaporizing zone from non-volatile materialtherein, and passing the vaporized ferrous chloride into a condensingzone; condensing the vaporized ferrous chloride in said condensing zoneto form liquid ferrous chloride by abstracting heat therefrom;introducing the liquid ferrous chloride thus produced into a reducingzone as a iine liquid spray, separately introducing into said reducingzone a gaseous medium, the essential active reducing ingredient of whichis hydrogen, for reaction with the ferrous chloride droplets of saidspray, so as'to reduce at least a substantial portion of the ferrouschloride to metallic iron, while maintaining the temperature in saidreducing zone at least as high as the melting point of the ferrouschloride; but below the melting point of said metallic iron; separatingthe products resulting from the reaction in said reducing zone betweensaid gaseous medium including hydrogen and the liquid ferrous chloridedroplets into (a) solid material including the metallic iron and (b)gaseous materials; including make-up HCl in said gaseous materials inamount required to provide the aforesaid relative proportions of HC1 andhydrogen in said chloridizing step and passing the resulting gaseousmaterials to said chloridizing zone as said gaseous mixture which issupplied to said chloridizing zone for use as aforesaid; removing thegaseous products of the reaction in said chloridizing zone from suchzone and separating therefrom a substantial amount of the water vaporcontent thereof, passing these remaining gases, from which water vaporhas been removed and to which make-up hydrogen is added, into saidreducing zone as said gaseous medium which is separately introduced intosaid reducing zone, and controlling and balancing the operations of theseveral steps of the process aforesaid by controlling the rate at whichliquid ferrous chloride is supplied to said reducing zone, the rate ofsupply of hydrogen to said reducing zone and the amount of make-up HClincluded in said gaseous materials passing to said chloridizing zone.

6. The process of preparing metallic iron from a solid ironoxide-containing material, comprising the steps of chloridizing asubstantial proportion of the iron oxide of said material to formferrous chloride by contacting said solid material in a chloridizingzone and at a temperature of at least 500 F. but below the melting pointof said ferrous chloride with a gaseous mixture containing, as essentialingredients, HCl and hydrogen and wherein the HC1 concentration is fromabout 5% to about 25% by volume based upon the total of hydrogen plusHC1 in said gaseous mixture, and preventing the reduction of iron to themetallic state by keeping said temperature always below the limit inrespect to HCl concentration as defined in the following table: passingthe remaining solid material as thus Temperature limit F.) below whichtemperature must be maintained HC1 concentration, pxilit by volume basedon aaworgrea chloridized 4fromsaidchloridizingezone tofavaporizing--`-zone, and there raxsing=1the Itemperature lthereof"` sufi ferrouschloride `byrabstractingheat .therefromg in tro-A 'ducinggthe liquidferrous, .chloride ,thus .f produced -1nto l a reducinglzone as"`anefvliquidf spraywseparatelyamtroducing into said reducing zone agaseous medium, the essential active reducing ingredient of which ishydrogen, for reaction with the ferrous chloride dropletsof said spray,so as to reduce at least a substantial portlon of the ferrous chlorideto metallic iron, while maintaining the temperature in said reducingzone at least as high as the melting point of ferrous chloride; butbelow the melting point of said metallic iron; passing all the materialsremaining after the reaction in said reducing zone to a separator andtherein raising the temperature of these materials up to the vaporizingtemperature of ferrous chloride at the pressure existing m saidseparator and thereby vaporizing ferrous chloride, separating the solidmetallic iron from the gaseous materials in said separator including HC1and ferrous chloride vapor; including make-up HC1 in said gaseousmaterials in amount required to provide the aforesaid relativeproportions of HCl and hydrogen in said chloridizing step and passingthe resulting gaseous materials to said chloridizing zone as the gaseousmixture which is supplied to said chloridizing zone for use asaforesaid; condensing the ferrous chloride contained in said resultinggaseous mixture to solid form in said chloridizing zone; removing thegaseous products of the reaction in said chloridizing zone from suchzone and separating therefrom a substantial amount of the water vaporcontent thereof, and passing these remaining gases, from which watervapor has been removed and to which make-up hydrogen is added, into saidreducing zone as said gaseous medium which is separately introduced intosaid reducing zone.

7. The process of preparing metallic iron from a solid ironoxide-containing material, comprising the steps of chloridizing asubstantial proportion of the iron oxide of said material to formferrous chloride by contacting said solid material in a chloridizingzone and at a temperature of at least 500 F. but below the melting pointof said ferrous chloride with a gaseous mixture containing, as essentialingredients, HCl and hydrogen and wherein the HCl concentration is fromabout 5% to about 25% by volume based upon the total of hydrogen plusHC1 in said gaseous mixture, and preventing the reduction of iron to themetallic state by keeping said temperature always below the limit inrespect to HCl concentration as defined in the following table:

Temperature limit F.) below which temperature must be maintained HC1concentration, pcxllt by volume based on HCH-Hz O1 about 5- and over..

passing the remaining solid material as thus chloridized from saidchloridizing zone to a vaporizing zone, and there raising thetemperature thereof suiciently t0 vaporize the ferrous chloride contentof this material; separating the vaporized ferrous chloride produced insaid vaporizing zone from the non-volatile material therein, and passingthe vaporized ferrous chloride into a condensing zone; condensing thevaporized ferrous chloride in said condensing zone to form liquidferrous chloride by abstracting heat therefrom; introducing the liquidferrous chloride thus produced into a reducing zone as a fine liquidspray, separately introducing into said reducing zone a gaseous medium,the essential active reducing ingredient of which is hydrogen, forreaction with the ferrous chloride droplets of said spray, so as toreduce at least a substantial portion of the ferrous chloride tometallic iron, while maintaining the temperature in said reducing zoneat least as high as the melting point of ferrous chloride; but below themelt- 22 1 fing point i of H"said 5*metallic irony cooling Ethe*products Jffffthe reaction '"insaid reducing' zone :to form al *solidmixture of *metallic firon and fnnreact'edL ferrous 'chloride and 1-remaining gaseous materials, lseparating-said L"solid f =mixturefv fromsaid`l gaseous materials" anderecovering'ythe metallic iron contentthereoflfasfa'productoffthe proc ess; including make-up HCl kin ,v saidgaseous materials in amount requiredeto'providedhe" aforesaid relativeproportionsvof-l-ICI and,hydrogen=fin:'fsaid chloridizing step andpassing the resulting gaseous materials to said #chloridizingzoneas-saidgaseousmixture which is. sup- -plied-tof saidchloridizing-zone'.forjuse as aforesaid; removing the gaseous productsof-the reaction "ine said chloridizing zone from such zone andseparating therefrom a substantial amount of the water vapor contentthereof, and passing these remaining gases, from which Water vapor hasbeen removed and to which hydrogen is added, into said reducing zone assaid gaseous medium which is separately introduced into said reducingzone.

8. The process of preparing metallic iron from a solid ironoxide-containing material, comprising the steps of chloridizing asubstantial proportion of the iron oxide of said material to formferrous chloride by contacting said solid material in a chloridizingzone and at a temperature of at least 500 F. but below the melting pointof said ferrous chloride with a gaseous mixture containing, as essentialingredients, HC1 and hydrogen and wherein the HC1 concentration is fromabout 5% to about 25% by volume based upon the total of hydrogen plusHC1 in said gaseous mixture, and preventing the reduction of iron to themetallic state by keeping said temperature always below the limit inrespect to HCl concentration as dened in the following table: passingthe remaining solid material as thus Temperature limit F.) below whichtemperature must be maintained HC1 concentration, pefrrclt by volumebased on H Cl-l-Ha C; about 5. 15 and oven.--

chloridized from said chloridizing zone to a vaporizing zone, and thereraising the temperature thereof suiciently to vaporize the ferrouschloride content of this material; separating the vaporized ferrouschloride produced in said vaporizing zone from the non-volatile materialtherein, and passing the vaporized ferrous chloride into a condensingzone; condensing the vaporized ferrous chloride in said condensing zoneto form liquid ferrous chloride by abstracting heat therefrom;introducing the liquid ferrous chloride thus produced into a reducingzone as a tine liquid spray, separately introducing into said reducingzone a gaseous medium, the essential active reducing ingredient of whichis hydrogen, for reaction with the ferrous chloride droplets of saidspray, so as to reduce at least a substantial portion of the ferrouschloride to metallic iron, while maintaining the temperature in saidreducing zone at least as high as the melting point of ferrous chloride,but below the melting point of said metallic iron; introducing an inertgas into said reducing zone as an annular stream surrounding said neliquid spray of ferrous chloride as the latter is introduced into saidreducing zone, so as to prevent premature initial contact between theferrous chloride droplets of said spray and the hydrogen separatelyintroduced into said reducing zone; separating the products resultingfrom the reaction in said reducing zone between said gaseous mediumincluding hydrogen and the liquid ferrous chloride droplets into (a)solid material including the metallic iron and (b) gaseous materials;including make-up HCl in said gaseous materials in amount required toprovide the aforesaid relative proportions of HCl and hydrogen in saidchloridizing step and passing the resulting gaseous materials to saidchloridizing zone as said gaseous mixture which is supplied to saidchloridizing zone for use as aforesaid; bleeding out and discarding someof the gaseousproducts from said chloridizing zone so as to prevent thebuilding up of the concentration of inert gases being recycled in thesystem more than a predetermined amount, removing from the remaininggases 23 24 from the chloridizng zone a substantial amount of the2,596,072 Graham et al. May 6, 1952 water content thereof, and passingthese remaining 2,663,633 Crowley et al. Dec. 22, 1953 gases, from whichwater vapor has been removed and to which mak-up hydrogeni is adgedf1into said educing 5 FOREIGN PATENTS zone as sai gaseous me ium w ic isseparate y intro- 346 921 Great Britain A pr. 23, 1931 duced Into Saidfeducmg 20ne- 723J7O3 Germany Dec 2, 1942 References Cited in the le ofthis patent OTHER REFERENCES UNITED STATES PATENTS lo AlCprehensivebTreatile on llnoranic gidh'lhegretica emistry, y Me or, vo. 1 pu is e y212 leii: @Si 272 i332 Lfmgmans Green & C0 1935 Pages 1 and -11-2,290,843 Kinney July 21, 1942

1. THE PROCESS OF PREPARING METALLIC IRON FROM A SOLID IRONOXIDE-CONTAINING MATERIAL, COMPRISING THE STEPS OF CHLORIDIZING ASUBSTANTIAL PROPORTION OF THE IRON OXIDE OF SAID MATERIAL TO FORMFERROUS CHLORIDE BY CONTACTING SAID SOLID MATERIAL IN A CHLORIDIZINGZONE AND AT A TEMPERATURE OF AT LEAST 500* F. BUT BELOW THE MELTINGPOINT OF SAID FERROUS CHLORIDE WITH A GASEOUS MIXTURE CONTAINING, ASESSENTIAL INGREDIENTS, HC1 AND HYDROGEN AND WHEREIN THE HCICONCENTRATION IS FROM ABOUT